1. Field of the Invention
The present invention relates to systems and methods for examining biological material. In particular, the invention relates to the analysis of images from scanned biological probe arrays comprising probe features of very small size, such as for instance probe features that are 8 μm or less across. Accurate analysis of small features sizes becomes increasingly more complicated as the feature size becomes smaller where elements of the scanning system may contribute to sources of error in the resulting image. For example, the scanning system may implement a light source focused to a spot and scanned across the probe array where the size of the spot is large in comparison to the size of the probe features and inter-feature spacing on a probe array where the spot size may produce “blurring” in the resulting image. In the present example, the described analysis may preferably be implemented with images generated from a scanning system using a CCD based architecture with a wide field of view which is described in greater detail below.
2. Related Art
Synthesized nucleic acid probe arrays, such as Affymetrix GeneChip® probe arrays, and spotted probe arrays, have been used to generate unprecedented amounts of information about biological systems. For example, the GeneChip® Human Genome U133 Plus 2.0 Array for expression applications available from Affymetrix, Inc. of Santa Clara, Calif., is comprised of one microarray containing 1,300,000 oligonucleotide features covering more than 47,000 transcripts and variants that include 38,500 well characterized human genes. Similarly, the GeneChip® Mapping 500K Array Set for genotyping applications available from Affymetrix, Inc. of Santa Clara, Calif., is comprised of two arrays, each capable of genotyping on average 250,000 SNPs (single nucleotide polymorphism). Analysis of expression or genotyping data from such microarrays may lead to the development of new drugs and new diagnostic tools.